Question

我需要连接来自两个不同表的数据，如下所示。只有一个SQL查询可以吗？如果＆＃34;键＆＃34;和＆＃34;名称＆＃34;在两个表上，然后它们是相同的。＆＃34;状态＆＃34;总是＆＃34; - ＆＃34;在table1和＆＃34; T＆＃34;在table2上。同时＆＃34;名称＆＃34;和＆＃34; comp＆＃34;两个表都匹配（例如：Name3-C和Name4-B）我试过和＃34; union＆＃34;和＆＃34;加入＆＃34;但还没有解决方案！

表1

t1.name     t1.time   t1.comp   t1.key   t1.status
name1        1          B         106        -
name2        2          B         -          -
name3        1          C         102        -
name4        3          B         103        -
name7        1          C         104        -

表2

t2.name     t2.time   t2.comp   t2.key    t2.status
name5        6          B         100        T
name6        5          B         -          T
name3        7          C         102        T
name4        9          B         103        T

结果应该是......

name      time1    time2   t.comp   t.key   t.status
name1        1       -       B       106       -  
name2        2       -       B        -        -
name3        1       7       C       102       T
name4        3       9       B       103       T
name5        -       6       C       100       T
name6        -       5       B        -        T
name7        1       -       C       104       -

提前谢谢！

Answer 1

如果我理解正确，您需要full outer join：

select coalesce(t1.name, t2.name) as name,
       t1.time as time1, t2.time as time2,
       coalesce(t1.comp, t2.comp) as comp,
       coalesce(t1.key, t2.key) as key,
       t2.status
from table1 t1 full outer join
     table2 t2
     on t1.key = t2.key and t1.name = t2.name;

Answer 2

Select * from table1
union all 
Select * from table2

假设表的模式相同。如果他们不只是将一个表中的字段添加到另一个表中。

Select field1,field2,NULL,NULL from table1
union all 
Select NULL,NULL,field3,field4 from table2

Answer 3

SELECT 
  T1.time AS Time1,
  T2.Time AS Time2,
  ISNULL(T1.COMP,T2.Comp) AS Comp,
  ISNULL(T1.Key,T2.Key)
FROM TABLE1 T1
FULL OUTER JOIN TABLE2 T2
ON T1.key = T2.key

SQL查询，连接两个表

3 个答案: